The present invention relates to the treatment of gastrointestinal disease, and/or cancer, and a method of weight gain, via the ingestion of polymeric compositions in humans, animals or birds in need of said treatment.
Under the conditions of intensive pig-rearing, post-weaning colibacillosis is ubiquitous. For example, intensive pig-rearing is used throughout Europe, United States and Australia. For example, in the United States, post-weaning colibacillosis is the most common cause of mortality in the weaner pig (Leman et al., 1986). The disease is associated with the proliferation of Escherichia coli bacteria in the anterior small intestine after weaning, and gives rise to either death, or the young weaner failing to make normal weight-gains. Other microbiological diseases are common and often accompany colibacillosis in pigs as well as in other animals in intensive rearing conditions, especially poultry.
In the past, attempts have been made to control disease by the ingestion of antimicrobial compositions or by vaccination, neither of which has proved entirely effective.
The rationale behind the lack of success surrounding ingestion of antimicrobial compositions has been the fact that proteinaceous feedstuffs and the contents of the gastrointestinal tract present a reactive and hazardous environment to any chemotherapeutic agent and hence, an in vitro active antimicrobial agent will often not be effective when used in vivo within the gastrointestinal tract.
Further, to be antimicrobially effective in a practical way, there is often the restrictive demand that the gastrointestinal disease controlling agent should reasonably maintain the very low microbiological content in the duodenum, yet the very high content in the lower parts of the intestine.
As well, it does not follow that even in vivo effective antimicrobials will give weight-gains, since it is common that even a cocktail of several such commercially used antimicrobials only gives rise to variable, partial or even negative relative weight-gains over control animals.
Accordingly, there is a need for improvements in the prevention and/or treatment of disease via ingestion of antimicrobial compositions in humans and/or animals and/or birds in need of said treatment. Furthermore, there is the need for the attainment of weight gains of said humans and/or animals and/or birds undergoing said treatment.
The present invention provides polymers and/or copolymers preferably derived from acrolein and having the polymeric repeating unit: 
wherein R is H or alkyl, usually C1 to C4 or this unit in hydrated, hemiacetal or acetal form and illustrated non-comprehensively of all possible structures, by the following formulae: 
wherein n is one or more and R is as defined above; hereinafter referred to as the xe2x80x9cSubject Polymersxe2x80x9d, as broad spectrum in vivo antimicrobials and/or anti-cancer agents suitable for treatment by the oral route.
It is known that the rate of passage of molecules across membranes has an inverse relationship to their molecular weights. Thus, it is widely and generally accepted in the art that molecules taken by the oral route and having molecular weight  less than 1000, will have their passage across the gut so restricted, and consequently any potential toxicity will be effectively minimised.
The Subject Polymers, being aldehydic, are especially reactive with protein. (In fact, in microbiological assays, the routine and facile method of quenching/destroying the activity of the Subject Polymersxe2x80x94is to add protein.) Hence, the Subject Polymers would not be expected to exhibit significant microbiological activity in the intestine, especially in the presence of proteinaceous feed.
Therefore, the present invention provides a method of prevention and/or treatment of gastrointestinal disease in humans, animals or birds resulting from the microbial infection of the gastrointestinal tract, and a method for increasing weight gain in humans, animals or birds having gastrointestinal disease and/or infection, comprising administering an effective amount to said humans, animals or birds of a pharmaceutical composition or feed additive, comprising an effective amount of the Subject Polymers together with a pharmaceutically or veterinarally acceptable carrier, diluent, adjuvant, excipient or controlled release system.
It is an object of the present invention to provide methods for the prevention and treatment of dysfunctional/pathological states in a human, animal or bird, especially, those states within the gastrointestinal tract associated with colibacillosis, diarrhoea, mortality and/or reduced weight gains.
The present invention is based upon a series of discoveries herein:
Firstly, it has now been discovered that the Subject Polymers, being of high molecular weight are inhibited in passage through biological membranes, and have facilitated applications in the gastrointestinal tract, since passage through the gut and into the bloodstream to potentially cause toxicity is minimised. In particular, it has been discovered that the Subject Polymers have molecular weights  greater than 1000, and generally have molecular weights  greater than 2000, which effectively minimise their passage across the intestinal membranes and as a result, it has been found herein that whilst the Subject Polymers exhibit toxicity following intra-venous injection, they exhibit no toxicity when administered orally. Hence it has been discovered that the Subject Polymers have mimimised toxicities and that they have associated advantages when used for chemotherapeutic purposes, in any species having gut membranes, for example, humans, animals or birds.
Generally, the Subject Polymers formed by ionic initiation/catalysis are more hydrophilic than those formed by free radical initiation/catalysis, and hydrophilicity of the Subject Polymers may generally be increased by inclusion within them of hydrophilic groups, especially carboxyl groups, or of hydrophilic monomers, especially acrylic acid. Particularly, carefully heating the Subject Polymers formed by ionic initiation/catalysis with ample air from room temperature to up to 100xc2x0 C., and preferably up to between 80-85xc2x0 C., produces the Subject Polymers having 0.1-5 moles of carboxyl groups/kg, aqueous soluble at the pH of the duodenum especially, and preferred for the applications in gastrointestinal tracts described and envisaged herein.
The Subject Polymers have the following properties:
The Subject Polymers have an unusually broad in vivo antimicrobial profile, providing a method of treatment of gastrointestinal disease in humans, animal or birds.
It has been shown that the Subject Polymers provide increased weight gains in humans, animals or birds.
It has also been shown that the Subject Polymers are in vivo anti-cancer agents.
According to a first embodiment of the invention there is provided a method of in vivo cancer treatment in humans, animals or birds comprising administering to said humans, animals or birds an effective amount of a pharmaceutical or veterinary composition or feed additive, comprising an effective amount of polymers and/or copolymers having the repeating polymeric unit: 
wherein R is H or alkyl, usually C1 to C4, or this unit in hydrated, hemiacetal or acetal form and illustrated non-comprehensively of all possible structures, by the following formulae: 
wherein n is one or more and R is as defined above; together with a pharmaceutically or veterinarally acceptable carrier, diluent, adjuvant, excipient and/or controlled release system.
According to a second embodiment of the invention there is provided a method for the treatment and/or prevention of gastrointestinal disease and/or infection and/or diarrhoea in humans, animals or birds resulting from a microbial infection of the gastrointestinal tract in said humans, animals or birds, comprising administering to said humans, animals or birds an effective amount of a pharmaceutical or veterinary composition or feed additive, comprising an effective amount of a polymer and/or copolymer as defined in the first embodiment of the invention, together with a pharmaceutically or veterinarally acceptable carrier, diluent, adjuvant, excipient and/or controlled release system.
According to a third embodiment of the invention there is provided a method of increasing weight gain in humans, animals or birds having cancer and/or gastrointestinal microbial disease and/or infection, in said humans, animals or birds, comprising administering to said humans, animals or birds an effective amount of a pharmaceutical or veterinary composition or feed additive, comprising an effective amount of a polymer and/or copolymer as defined in the first embodiment of the invention, together with a pharmaceutically or veterinarally acceptable carrier, diluent, adjuvant, excipient and/or controlled release system.
In terms of the Subject Polymers being a prevention and/or treatment for gastrointestinal disease, it has now been shown that farm-piglets given the Subject Polymers ad libitum in their drinking water, have reduced numbers of diarrhoea days and lower counts of E. coli in their excreta. Moreover, the effect as proposed, is markedly greater than the partial effect exhibited by the administration of commercial antimicrobial agents together with vaccination.
In addition, it has now been discovered that the Subject Polymers in a polymeric controlled-release system as well as leading to fewer diarrhoea days in the animal, also gave rise to extraordinarily high weight-gains. As exemplified in Example 17, piglets displayed lower mortality, and weight gains of some 46% above control piglets.
Therefore, it is proposed that the Subject Polymers should be provided as an additive to the animal""s solid feed, in the form of a polymeric controlled-release system, since then, the Subject Polymers would be released slowly and mainly in the duodenum. Further, it is now proposed that having the Subject Polymers in a controlled-release system will reduce any destructive chemical reaction between the Subject Polymers and either constituents of the gastro-intestinal tract or the proteinaceous feed, especially during the essential pre-heat sterilisation of the feed. Furthermore, any rejection by the animal due to taste, will be reduced.
When using the Subject Polymers for the treatment of disease and/or infection in humans, animals or birds in need of treatment, for example in piglets having diarrhoea associated with colibacillosis, it is preferred to begin dosing immediately after weaning and to always continue for the next 5 days, sometimes for the next 30 days, but preferably at least for the next 15 days after weaning; at any time that such symptoms of diarrhoea are observed. Treatment in a controlled-release form is preferred and containing theoretically 5%-50% w/w Subject Polymers but preferably, 20%-30% w/w. Preferably the controlled-release form/pellet is added to the feed, either during production of the feed or during feeding such that the feed contains 1%-20% w/w and preferably 2%-8% w/w of pellet. If for example a piglet of 5 kg daily eats 500 g of feed with 4% w/w controlled-release pellet containing 25% w/w Subject Polymersxe2x80x94this calculates to a dose rate of Subject Polymers of 1000 mg/kg(liveweight)/day; in a controlled-release form a dose rate of 50-5000 mg/kg/day is practical but 500-2500 mg/kg/day is preferred. Smaller dose rates of 25-500 mg/kg/day should be used when the Subject Polymers are given in a non-controlled-release form. Dose protocols and rates are similar for other microbiological infections and for cancer.
Both the in vivo antimicrobial activity in the presence of relatively huge quantities of reactive proteins in the gastro-intestinal tract, and the range of chemotherapeutic activities of the Subject Polymers, revealed herein, are surprising. Also, in unpublished work, the Subject Polymers have been found to exhibit significant anti-coagulant activities in human or a range of various animal bloods. This particular range of surprising in vivo activities suggests that unexpectedly, the Subject Polymers have such activities related to lectin-selectin-integrin type adsorptive inter-actions.
Compositions for administration in the method of the invention may be prepared by means known in the art for the preparation of compositions (such as in the art of veterinary and pharmaceutical compositions) including blending, grinding, homogenising, suspending, dissolving, emulsifying, dispersing and where appropriate, mixing of the Subject Polymers together with selected excipients, diluents, carriers and adjuvants.
For oral administration, the pharmaceutical or veterinary composition may be in the form of tablets, lozenges, pills, troches, capsules, elixirs, powders, including lyophilised powders, solutions, granules, suspensions, emulsions, syrups and tinctures. Slow-release, or delayed-release, forms may also be prepared, for example in the form of coated particles, multi-layer tablets or microgranules.
It is preferred that the controlled release system comprises a pH-sensitive, cross-linked, water-absorbent pellet, which when wet is a gel.
Solid forms for oral administration may contain pharmaceutically or veterinarally acceptable binders, sweeteners, disintegrating agents, diluents, flavourings, coating agents, preservatives, lubricants and/or time delay agents. Suitable binders include gum acacia, gelatin, corn starch, gum tragacanth, sodium alginate, carboxymethylcellulose or polyethylene glycol. Suitable sweeteners include sucrose, lactose, glucose, aspartame or saccharine. Suitable disintegrating agents include corn starch, methylcellulose, polyvinylpyrrolidone, xanthan gum, bentonite, alginic acid or agar. Suitable diluents include lactose, sorbitol, mannitol, dextrose, kaolin, cellulose, calcium carbonate, calcium silicate or dicalcium phosphate. Suitable flavouring agents include peppermint oil, oil of wintergreen, cherry, orange or raspberry flavouring. Suitable coating agents include polymers or copolymers of acrylic acid and/or methacrylic acid and/or their esters, and/or their amides, waxes, fatty alcohols, zein, shellac or gluten. Suitable preservatives include sodium benzoate, vitamin E, alpha-tocopherol, ascorbic acid, methyl paraben, propyl paraben or sodium bisulphite. Suitable lubricants include magnesium stearate, stearic acid, sodium oleate, sodium chloride or talc. Suitable time delay agents include glyceryl monostearate or glyceryl distearate.
Liquid forms for oral administration may contain, in addition to the above agents, a liquid carrier. Suitable liquid carriers include water, oils such as olive oil, peanut oil, sesame oil, sunflower oil, safflower oil, arachis oil, coconut oil, liquid paraffin, ethylene glycol, propylene glycol, polyethylene glycol, ethanol, propanol, isopropanol, glycerol, fatty alcohols, triglycerides or mixtures thereof.
Suspensions for oral administration may further comprise dispersing agents and/or suspending agents. Suitable suspending, agents include sodium carboxymethylcellulose, methylcellulose, hydroxypropylmethyl-cellulose, poly-vinyl-pyrrolidone, sodium alginate or cetyl alcohol. Suitable dispersing agents include lecithin, polyoxyethylene esters of fatty acids such as stearic acid, polyoxyethylene sorbitol mono- or di-oleate, -stearate or -laurate, polyoxyethylene sorbitan mono- or di-oleate, -stearate or -laurate and the like.
The emulsions for oral administration may further comprise one or more emulsifying agents. Suitable emulsifying agents include dispersing agents as exemplified above or natural gums such as gum acacia or gum tragacanth.
According to a fourth embodiment of the invention there is provided a method of producing pellets, the pellets comprising polymers and/or copolymers as defined in the first embodiment of the invention, together with a pharmaceutically or veterinarally acceptable carrier, diluent, adjuvant, excipient and/or controlled release system, mainly within a polymeric matrix. The method comprising adding a polymeric matrix to a solution, suspension or emulsion of the polymers and/or copolymers as defmed in the first embodiment of the invention.
According to a fifth embodiment of the invention there is provided a method of producing pellets or like solid composition, the pellets comprising polymers and/or copolymers as defined in the first embodiment of the invention, mainly within a polymeric matrix, said method as defined in the fourth embodiment of the invention and comprising the steps of:
(i) dissolving said polymers and/or copolymers in an aqueous alkaline or basic solution;
(ii) neutralising said solution with acid;
(iii) adding to said neutralised solution insoluble, cross-linked, absorbent polymers of acrylic acid and/or copolymers of acrylamide and acrylic acid, to form wet swollen pellets; and
(iv) optionally, wholly or partially drying said wet swollen pellets.
The so-formed wet, swollen pellets may be used either wet, partially dried or wholly dried, as an additive to, for example, animal feed. This system is further designed so that the carboxyl-containing groups of the outer polymeric matrix cause the Subject Polymers to remain essentially contained within the matrix when in the acidic environment of the stomach. However, in the alkaline environment of the duodenum, the carboxyl groups of the matrix become ionised and mutually-repelling, and the pellet rapidly swells to allow the Subject Polymers, aided by repulsion among their own ionic groups, to be excluded by a diffusion process, approximately matching the speed of passage of feed through the duodenum.
In this invention, the term, xe2x80x9ccontrolled release systemxe2x80x9d is used in the same context as that in, and includes the same range of examples as quoted in xe2x80x9cControlled Drug Deliveryxe2x80x9d (Robinson and Lee, 1987). Many other pH-sensitive controlled-release systems which are known in the art (Robinson and Lee, 1987) may be substituted for the polymer of acrylic acid or copolymer of acrylamide and acrylic acid. For example, soluble and anionic or insoluble, cross-linked and anionic, cellulosic systems or soluble and anionic, or insoluble, cross-linked and anionic polymers derived from any generic acrylic acid and/or its derivatives. Such cross-linked and insoluble polymers are preferred since they swell and also, are less likely to be metabolised.
In summary, the compositions described herein may be used to control cancer and/or microbiological disease and especially result in greater weights of humans, animals or birds having gastrointestinal infections. The invention is applicable in humans, animals or birds having microbiological diseases of the gastrointestinal tract for example, Escherichia coli. A preferred use is to bring about greater weights in newly-weaned piglets having diarrhoea and associated with the proliferation of Escherichia coli bacteria in the anterior small intestine. The invention may be applicable in humans having gastrointestinal disease, for example, from Staphylococcus aureus and/or Helicobactor pylori bacteria.
The invention will now be described with reference to specific Examples, which should not be construed as limiting on the scope thereof.